激光超声检测中干涉特征提取算法的研究  

Research on Interference Energy Calculation Method in Laser Ultrasonic Technique

作　　者：张超[1] 季宏丽[1] 裘进浩[1] 吴郁程[1] 

机构地区：[1]南京航空航天大学航空宇航学院机械结构力学及控制国家重点实验室,南京江苏210016

出　　处：《光学学报》2014年第7期150-158,共9页Acta Optica Sinica

基　　金：国家863计划(2013AA041105);国家重点实验室自主课题团队项目(0513G01);中央高校基本科研业务费专项资金;江苏省普通高校研究生科研创新计划(CXZZ13_0157);江苏高校优势学科建设工程资助项目

摘　　要：为了有效地检测结构中的损伤位置及其形状,开展了基于超声导波干涉特征提取算法的损伤成像技术研究。在波场可视化的基础上,从波场历程中进一步分析了损伤对超声导波传播的影响;为了提取损伤附近超声导波干涉的能量,采用时间与空间域上的傅里叶变换对波场中的入射波和反射波进行分离,并根据计算出的干涉能量分布完成了损伤的成像;由于损伤产生的干涉能量在空间上的分布较广,为了减少损伤区域外的干涉能量,提高图像中损伤形状的分辨率,利用实Morlet小波分析的方法对宽频信号进行处理,提取窄带信号分量再进行干涉能量计算,提高了损伤成像的信噪比。In order to evaluate the position and shape of the structural damage, a damage visualization technique using interference energy calculation method is presented. Based on the wavefield visualization technique, this study analyzes the effects on ultrasonic wave propagation caused by the damage. To extract the interference energy from the wavefield near the damage, Fourier transform in both time and space domains is used to separate the incident and reflected wavefields and then the inference energy is calculated to image the damage. Due to the interference energy caused by the damage spreads widely, Morlet wavelet transform is used in broadband signal processing to improve the resolution of the damage imaging. After narrowband signal extraction, interference energy calculation is followed and the signal to noise ratio of the damage imaging is improved.

关 键 词：激光技术 激光超声 损伤成像 干涉能量 小波变换 

分 类 号：TB551[理学—物理] TB553[理学—声学]